7.2 Short term memory
A. Explanation of short-term memory
- Short-term memory is a type of memory that holds a limited amount of information for a short period of time.
- It is also known as working memory, and it is the information that we are currently processing or actively thinking about.
- Short-term memory has a limited capacity, which means we can only hold a small amount of information at a time, usually around 7 plus or minus 2 items.
- The duration of short-term memory is also limited, typically lasting only a few seconds to a minute, unless the information is rehearsed or encoded into long-term memory.
- Short-term memory is necessary for many cognitive tasks, such as reading, problem-solving, and decision-making, and it plays a crucial role in our daily lives.
B. Importance of studying short-term memory
I. Understanding the nature of human cognition
- Short-term memory is a fundamental aspect of human cognition and a critical component of many cognitive processes, such as attention, perception, and decision-making.
- By studying short-term memory, researchers can gain insights into how our brain processes information, how we control our attention, and how we make decisions based on limited information.
II. Developing strategies for learning and memory
- Short-term memory is the gateway to long-term memory, and effective encoding and retrieval of information depend on the functioning of short-term memory.
- By understanding how short-term memory works, researchers can develop strategies and techniques to help individuals learn and remember new information more effectively.
III. Improving educational practices
- Short-term memory plays a vital role in learning and academic achievement, particularly in areas such as reading comprehension, problem-solving, and math.
- By studying short-term memory, researchers can identify effective instructional practices and develop interventions to help students with short-term memory difficulties.
IV. Understanding the effects of aging and neurodegenerative diseases
- Short-term memory declines with age and is often impaired in individuals with neurodegenerative diseases such as Alzheimer’s.
- By studying short-term memory, researchers can better understand the nature of cognitive aging and neurodegenerative diseases and develop strategies to prevent or delay cognitive decline.
V. Understanding the brain and its functions
- Short-term memory is associated with specific brain regions and neural networks, and understanding these neural mechanisms can shed light on how the brain processes and stores information.
- By studying short-term memory, researchers can gain insights into the workings of the brain and its functions, which can have implications for treating neurological disorders and enhancing brain function.
II. Definition of Short-term Memory
A. Explanation of working memory
I. Definition and components of working memory
- Working memory is a type of short-term memory that involves the active maintenance and manipulation of information.
- It consists of three components: the phonological loop, the visuospatial sketchpad, and the central executive.
II. Phonological loop
- The phonological loop is responsible for processing and storing verbal information, such as words and numbers.
- It is divided into two subcomponents: the phonological store, which holds auditory information for a few seconds, and the articulatory rehearsal process, which allows us to repeat or manipulate the stored information.
III. Visuospatial sketchpad
- The visuospatial sketchpad is responsible for processing and storing visual and spatial information, such as shapes, colors, and locations.
- It can be divided into two subcomponents: the visual cache, which holds visual information, and the inner scribe, which processes spatial information.
IV. Central executive
- The central executive is responsible for coordinating the information processed by the phonological loop and the visuospatial sketchpad and integrating it with information from long-term memory.
- It is also responsible for controlling attention and shifting focus between tasks.
V. Functioning and capacity of working memory
- Working memory has a limited capacity, typically around 7 plus or minus 2 items, and its duration is relatively short, ranging from a few seconds to a minute.
- The capacity and duration of working memory can be improved through practice and training.
- Working memory is necessary for many cognitive tasks, such as problem-solving, reasoning, and decision-making, and it plays a crucial role in our daily lives.
VI. Disorders and deficits in working memory
- Deficits in working memory can result from brain damage, neurological disorders, or developmental disorders such as ADHD.
- Deficits in working memory can impact academic achievement, particularly in areas such as reading, math, and problem-solving.
- Interventions such as cognitive training and working memory exercises can help improve working memory performance in individuals with deficits.
B. Capacity of short-term memory
I. Definition of short-term memory capacity
- Short-term memory capacity is the maximum amount of information that can be held in short-term memory at one time.
- It is commonly measured using tasks such as digit span, in which participants are asked to repeat back a list of digits in the correct order.
II. Theories of short-term memory capacity
- There are several theories of short-term memory capacity, including Miller’s “magic number 7,” which suggests that short-term memory can hold around 7 plus or minus 2 items.
- Other theories propose that short-term memory capacity depends on the complexity and nature of the information being stored, rather than a fixed number.
III. Factors that influence short-term memory capacity
- Short-term memory capacity can be influenced by various factors, such as age, cognitive abilities, and attention.
- Individuals with higher cognitive abilities, such as working memory capacity, tend to have a higher short-term memory capacity.
IV. Techniques for improving short-term memory capacity
- Techniques such as chunking, which involves grouping items together to increase their meaningfulness, can improve short-term memory capacity.
- Other techniques, such as repetition and rehearsal, can also enhance short-term memory capacity by increasing the duration of the memory trace.
V. Limitations of short-term memory capacity
- Short-term memory capacity is limited and can be easily overloaded, leading to forgetting and errors.
- The limited capacity of short-term memory highlights the importance of encoding and transferring information into long-term memory, where it can be stored and retrieved more reliably.
VI. Implications of short-term memory capacity
- The capacity of short-term memory has implications for many cognitive tasks, such as problem-solving, decision-making, and language comprehension.
- Understanding the capacity of short-term memory can help researchers and educators design effective learning strategies and interventions to enhance memory performance.
C. Duration of short-term memory
I. Definition of short-term memory duration
- Short-term memory duration is the length of time that information can be held in short-term memory before it is lost or forgotten.
- The duration of short-term memory is typically measured using tasks such as the Brown-Peterson task, in which participants are asked to remember a list of items for a short period of time.
II. Theories of short-term memory duration
- There are several theories of short-term memory duration, including decay theory, which suggests that information is lost from short-term memory over time due to the decay of the memory trace.
- Other theories propose that short-term memory duration is influenced by factors such as interference and attention.
III. Factors that influence short-term memory duration
- Short-term memory duration can be influenced by various factors, such as the type and complexity of the information being stored, as well as attentional demands.
- Short-term memory duration can also be affected by interference from other information or distractions.
IV. Techniques for improving short-term memory duration
- Techniques such as rehearsal, which involves repeating the information to be remembered, can improve short-term memory duration by maintaining the memory trace.
- Other techniques, such as elaboration, which involves linking new information to existing knowledge, can also enhance short-term memory duration by creating stronger memory traces.
V. Limitations of short-term memory duration
- Short-term memory duration is limited, with most information lasting only a few seconds to a minute.
- The limited duration of short-term memory highlights the importance of transferring information into long-term memory, where it can be stored and retrieved more reliably.
VI. Implications of short-term memory duration
- The duration of short-term memory has implications for many cognitive tasks, such as reading, language comprehension, and decision-making.
- Understanding the duration of short-term memory can help researchers and educators design effective learning strategies and interventions to enhance memory performance.
III. Types of Short-term Memory
I. Phonological or auditory short-term memory
- Phonological or auditory short-term memory refers to the ability to store and manipulate auditory information, such as spoken words or sounds.
- The phonological loop, proposed by Baddeley and Hitch, is a theoretical model that explains how auditory information is maintained and manipulated in short-term memory.
II. Visuospatial short-term memory
- Visuospatial short-term memory refers to the ability to store and manipulate visual and spatial information, such as the location of objects or shapes.
- The visuospatial sketchpad, proposed by Baddeley and Hitch, is a theoretical model that explains how visual and spatial information is maintained and manipulated in short-term memory.
III. Episodic buffer
- The episodic buffer is a component of working memory that integrates and temporarily stores information from different sources, including auditory and visual information.
- The episodic buffer is proposed to play a crucial role in complex cognitive tasks such as problem-solving and decision-making.
IV. Tactile short-term memory
- Tactile short-term memory refers to the ability to store and manipulate tactile or haptic information, such as the shape or texture of objects.
- Tactile short-term memory is less studied compared to phonological and visuospatial short-term memory.
V. Semantic short-term memory
- Semantic short-term memory refers to the ability to store and manipulate meaning-based information, such as the definitions of words or concepts.
- Semantic short-term memory is thought to be supported by the same neural systems as long-term memory.
VI. Motor short-term memory
- Motor short-term memory refers to the ability to store and manipulate motor-based information, such as the movements of the body or limbs.
- Motor short-term memory is important for tasks that require motor planning and execution, such as sports and dance.
VII. Cross-modal short-term memory
- Cross-modal short-term memory refers to the ability to integrate and manipulate information from different sensory modalities, such as auditory and visual information.
- Cross-modal short-term memory is important for tasks that require multisensory integration, such as speech perception.
IV. Encoding and Retrieval
Already covered in encoding and remembering module
V. Theories of Short-term Memory
A. Modal model of memory
The modal model of memory, proposed by Atkinson and Shiffrin in 1968, is a theoretical framework that describes the process of memory from sensory input to long-term storage.
I. Sensory memory
- Sensory memory is the first stage of the modal model of memory, in which sensory input from the environment is briefly registered.
- Sensory memory is divided into iconic memory, which registers visual information, and echoic memory, which registers auditory information.
II. Short-term memory
- Short-term memory is the second stage of the modal model of memory, in which information that is attended to in sensory memory is transferred to short-term memory for temporary storage.
- Short-term memory has a limited capacity and duration, and is responsible for maintaining information that is currently in use or being actively processed.
III. Working memory
- Working memory is a more recent theoretical model that has been proposed as an updated version of short-term memory.
- Working memory includes a limited capacity storage system for maintaining information, as well as an attentional control system for manipulating and processing the stored information.
IV. Long-term memory
- Long-term memory is the third and final stage of the modal model of memory, in which information that is rehearsed or elaborated upon in short-term memory is transferred to long-term storage for permanent storage.
- Long-term memory has an unlimited capacity and duration, and is responsible for storing information that can be retrieved and used at a later time.
- Retrieval is the process of accessing information that has been stored in long-term memory and bringing it back to consciousness.
- Retrieval can be influenced by various factors, such as the strength of the memory trace, the context in which the information was encoded, and the cues provided during retrieval.
VI. Criticisms of the modal model of memory
- The modal model of memory has been criticized for oversimplifying the complex processes involved in memory, such as the role of attention and perception in memory formation.
- The modal model of memory has also been criticized for ignoring the importance of individual differences in memory, such as differences in cognitive abilities and strategies.
Despite its limitations, the modal model of memory remains a foundational framework for understanding the processes involved in memory formation and retrieval.
B. Working memory model
The working memory model is a theoretical framework proposed by Baddeley and Hitch in 1974 to explain the active processing and manipulation of information in short-term memory.
I. Central executive
- The central executive is the main control center of the working memory system, responsible for coordinating and regulating the flow of information.
- The central executive is involved in attentional control, decision making, planning, and problem solving.
II. Phonological loop
- The phonological loop is a subcomponent of working memory that deals with verbal and auditory information.
- The phonological loop includes two subsystems: the phonological store, which stores speech-based information for a short period of time, and the articulatory loop, which rehearses and manipulates the stored information.
III. Visuospatial sketchpad
- The visuospatial sketchpad is a subcomponent of working memory that deals with visual and spatial information.
- The visuospatial sketchpad is responsible for temporarily storing and manipulating mental images, spatial relationships, and other visual-spatial information.
IV. Episodic buffer
- The episodic buffer is a subcomponent of working memory that acts as a temporary storage system for integrating information from different modalities and sources.
- The episodic buffer is responsible for binding together information from the phonological loop, visuospatial sketchpad, and long-term memory into a coherent representation.
V. Interaction between components
- The components of working memory are interdependent and interact with each other to enable the active processing and manipulation of information.
- The central executive plays a key role in coordinating and integrating information from the phonological loop, visuospatial sketchpad, and episodic buffer.
VI. Applications and implications
- The working memory model has important applications in fields such as education, psychology, and neuroscience.
- The working memory model has been used to develop interventions for improving working memory capacity in individuals with cognitive impairments or learning disabilities.
- The working memory model has also been used to study the neural and cognitive mechanisms underlying working memory function and dysfunction.
Despite its popularity, the working memory model has also faced criticism and debate, particularly regarding the nature and function of the central executive and the interaction between working memory and long-term memory. Nevertheless, the working memory model remains a widely used and influential theoretical framework for understanding the active processing and manipulation of information in short-term memory.
C. Baddeley’s model of working memory
Baddeley’s model of working memory is a refined version of the original working memory model proposed by Baddeley and Hitch in 1974.
I. Components of working memory
- Baddeley’s model proposes three main components of working memory: the phonological loop, the visuospatial sketchpad, and the central executive.
- The phonological loop deals with verbal and auditory information, while the visuospatial sketchpad deals with visual and spatial information.
- The central executive is responsible for coordinating and regulating the flow of information between the phonological loop, visuospatial sketchpad, and long-term memory.
II. Phonological loop
- The phonological loop includes two subsystems: the phonological store and the articulatory loop.
- The phonological store is a passive storage system that temporarily holds speech-based information.
- The articulatory loop is an active rehearsal system that helps maintain and manipulate the stored information through subvocal rehearsal.
III. Visuospatial sketchpad
- The visuospatial sketchpad includes two subsystems: the visual cache and the inner scribe.
- The visual cache stores visual information about shapes, colors, and patterns.
- The inner scribe deals with spatial information and coordinates the movement of visual images in the mind’s eye.
IV. Central executive
- The central executive is a flexible and dynamic system that controls attention, planning, decision making, and problem solving.
- The central executive has limited capacity and is responsible for allocating cognitive resources to the phonological loop and visuospatial sketchpad as needed.
- The central executive is also involved in integrating information from working memory and long-term memory through the episodic buffer.
V. Episodic buffer
- The episodic buffer is a temporary storage system that integrates and binds information from the phonological loop, visuospatial sketchpad, and long-term memory into a multimodal representation.
- The episodic buffer helps construct a sense of time, place, and context for the integrated information.
VI. Applications and implications
- Baddeley’s model of working memory has been used to explain a wide range of cognitive phenomena, such as language processing, spatial navigation, and problem solving.
- The model has also been used to develop interventions for improving working memory function in individuals with cognitive impairments or learning disabilities.
- The model has contributed to our understanding of the neural and cognitive mechanisms underlying working memory, attention, and executive control.
Despite its strengths, Baddeley’s model of working memory has also faced criticism and refinement over the years, particularly regarding the nature and function of the central executive and the interaction between working memory and long-term memory. Nevertheless, Baddeley’s model remains a widely accepted and influential theoretical framework for understanding the complex cognitive processes involved in working memory.
VI. Short-term Memory and Everyday Life
A. Importance of short-term memory in daily life
Short-term memory plays an important role in our daily lives.
I. Cognitive tasks
- Short-term memory is essential for performing a wide range of cognitive tasks, such as reading, writing, arithmetic, problem solving, and decision making.
- Without short-term memory, it would be difficult to hold and manipulate information in mind, make connections between different pieces of information, and apply knowledge to new situations.
II. Learning and education
- Short-term memory is critical for learning and education, as it enables us to store and process new information, such as new vocabulary, concepts, and facts.
- Short-term memory also allows us to practice and consolidate our learning through repetition and retrieval, leading to the formation of long-term memory.
III. Communication and social interaction
- Short-term memory plays an important role in communication and social interaction, as it allows us to follow a conversation, remember what was said, and respond appropriately.
- Short-term memory also enables us to recognize and remember faces, voices, and other sensory information that contribute to social interactions.
IV. Daily activities and routines
- Short-term memory helps us carry out daily activities and routines, such as remembering a shopping list, a phone number, or a schedule.
- Short-term memory also allows us to navigate our environment, remember directions, and avoid obstacles.
V. Emergency situations
- Short-term memory can be critical in emergency situations, as it allows us to process and respond to new and changing information, make decisions quickly, and coordinate our actions.
- Short-term memory also helps us remember emergency procedures and protocols, such as fire drills or first aid.
B. Strategies for improving short-term memory
I. Attention and focus
- One of the main reasons for forgetting information in short-term memory is a lack of attention and focus.
- To improve short-term memory, it is important to pay close attention to the information being presented, eliminate distractions, and avoid multitasking.
II. Repetition and rehearsal
- Repeating or rehearsing information can help to maintain it in short-term memory for longer periods of time.
- Examples of strategies that use repetition and rehearsal include verbal repetition, writing down information, and creating mental images or associations.
- Chunking involves breaking down information into smaller, more manageable chunks or groups.
- This can make it easier to remember information and reduce the cognitive load on short-term memory.
- Examples of strategies that use chunking include grouping numbers or letters into meaningful patterns, or breaking down a long list into smaller categories.
IV. Mnemonic devices
- Mnemonic devices are memory aids that use associations or visual images to help remember information.
- Examples of mnemonic devices include acronyms, rhymes, songs, and memory palaces.
V. Active retrieval and testing
- Practicing active retrieval and testing can help to consolidate information in short-term memory and transfer it to long-term memory.
- Examples of strategies that use active retrieval and testing include taking quizzes or tests, practicing retrieval exercises, and self-testing.
VI. Sleep and rest
- Adequate sleep and rest are important for memory consolidation and retention.
- Sleep helps to consolidate information in long-term memory and clear out irrelevant information from short-term memory.
- To improve short-term memory, it is important to prioritize restful sleep and avoid sleep deprivation.
C. Short-term memory and aging
As we age, our short-term memory abilities may decline due to a variety of factors.
I. Changes in brain structure and function
- As we age, there are changes in brain structure and function that can affect short-term memory.
- For example, there may be a decline in the size and connectivity of the hippocampus, a brain region critical for memory formation.
II. Health conditions and medication
- Certain health conditions and medications can also affect short-term memory in older adults.
- For example, depression, anxiety, and sleep disorders can all affect memory performance.
- Medications that affect the brain, such as sedatives and anti-anxiety drugs, can also impair short-term memory.
III. Lifestyle factors
- Lifestyle factors, such as physical exercise, diet, and stress, can affect short-term memory in older adults.
- Regular exercise has been shown to improve cognitive function, including short-term memory.
- A healthy diet, rich in fruits, vegetables, and omega-3 fatty acids, may also promote cognitive health.
- Chronic stress has been shown to have negative effects on cognitive function, including short-term memory.
IV. Strategies for improving short-term memory in older adults
- There are various strategies that can be used to improve short-term memory in older adults.
- For example, using memory aids, such as calendars or digital reminders, can help to compensate for memory deficits.
- Engaging in mentally stimulating activities, such as crossword puzzles or reading, may also help to maintain cognitive function.
- Social interaction and engagement may also be beneficial for cognitive health.
V. Importance of seeking medical advice
- If short-term memory problems persist and interfere with daily activities, it is important to seek medical advice.
- A healthcare professional can assess memory function, identify any underlying health conditions or medication-related issues, and provide appropriate treatment or referrals.
VII. Short-term Memory Disorders
A. Causes and symptoms of short-term memory disorders
Short-term memory disorders can be caused by a variety of conditions and factors, and may present differently depending on the individual.
I. Causes of Short-term Memory Disorders
- Head injuries: A head injury can cause damage to the brain and affect short-term memory.
- Medical conditions: Various medical conditions can affect short-term memory, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and stroke.
- Alzheimer’s disease: Alzheimer’s disease is a progressive brain disorder that affects memory, thinking, and behavior. It is characterized by the gradual loss of brain cells and a decline in cognitive function.
- Parkinson’s disease: Parkinson’s disease is a degenerative disorder of the nervous system that can affect movement, as well as memory and thinking skills.
- Huntington’s disease: Huntington’s disease is a genetic disorder that causes the breakdown of nerve cells in the brain. It can affect movement, cognition, and behavior.
- Multiple Sclerosis: Multiple sclerosis is a disease that affects the central nervous system, including the brain and spinal cord. It can cause a variety of symptoms, including memory problems.
- Stroke: A stroke occurs when blood flow to the brain is disrupted, leading to brain damage. Depending on the location of the damage, a stroke can cause memory problems and other cognitive deficits.
- Substance abuse: Substance abuse, such as alcohol or drug abuse, can damage the brain and affect short-term memory.
- Alcohol-related memory impairment: Long-term heavy alcohol consumption can damage the brain and affect memory, especially short-term memory.
- Drug-related memory impairment: Substance abuse, such as cocaine or methamphetamine use, can cause brain damage and memory problems.
- Medications: Certain medications can have side effects that affect short-term memory, such as benzodiazepines and antipsychotics.
- Stress and anxiety: High levels of stress and anxiety can affect short-term memory, as well as other cognitive functions.
II. Symptoms of Short-term Memory Disorders
- Difficulty learning new information: People with short-term memory disorders may have difficulty learning and remembering new information, such as new names or phone numbers.
- Difficulty remembering recent events: People with short-term memory disorders may have trouble remembering recent events or conversations, even if they were important.
- Difficulty following instructions: People with short-term memory disorders may have trouble following instructions or completing tasks that require short-term memory, such as cooking or cleaning.
- Repetition: People with short-term memory disorders may repeat questions or statements because they do not remember asking or saying them.
- Misplacing items: People with short-term memory disorders may misplace items frequently, as they do not remember where they put them.
B. Diagnosis and treatment
- Clinical evaluation: A doctor or mental health professional may conduct a clinical evaluation to assess the patient’s memory function, cognitive abilities, and medical history.
- Neuropsychological testing: Neuropsychological testing involves a series of standardized tests and tasks that assess various aspects of cognitive function, including memory.
- Brain imaging: Brain imaging, such as an MRI or CT scan, may be used to identify brain damage or other abnormalities that could be causing memory problems.
- Medication: Depending on the underlying cause of the short-term memory disorder, medication may be prescribed to treat the condition. For example, medication used to treat Alzheimer’s disease may be prescribed for patients with memory problems caused by the disease.
- Cognitive-behavioral therapy: Cognitive-behavioral therapy (CBT) may be used to help patients develop coping strategies and improve memory function. CBT can involve techniques such as memory training, problem-solving skills, and stress management.
- Lifestyle changes: In some cases, lifestyle changes may be recommended to improve memory function. This could include getting regular exercise, eating a healthy diet, reducing stress, and getting enough sleep.
- Assistive devices: Assistive devices, such as electronic organizers, can help patients with short-term memory problems remember appointments, tasks, and other important information.
C. Strategies for coping with short-term memory disorders
Coping with short-term memory disorders can be challenging, but there are strategies that can help individuals manage their symptoms and improve their daily functioning.
I. Memory aids
- Use of electronic organizers, calendars, and reminders on a phone or computer to help remember important appointments, events, and tasks.
- Writing notes or lists to help remember important information or tasks.
- Labeling objects or using color-coded systems to help with organization and memory.
II. Memory techniques
- Mnemonics, such as acronyms or visual imagery, to help remember information.
- Chunking information into smaller groups to improve recall.
- Rehearsing information through repetition or recitation to improve memory retention.
III. Lifestyle changes
- Getting regular exercise, which can help improve memory and cognitive function.
- Eating a healthy diet that includes brain-boosting nutrients, such as omega-3 fatty acids, antioxidants, and B vitamins.
- Getting enough sleep, which can help consolidate memories and improve overall cognitive function.
IV. Emotional support
- Joining a support group for individuals with memory disorders can provide a sense of community and emotional support.
- Seeking counseling or therapy to help cope with the emotional impact of memory problems.
V. Assistive devices
- Using assistive devices, such as hearing aids or magnifying glasses, to help with sensory impairments that may be contributing to memory problems.
- Utilizing medication reminders or pill dispensers to help with medication management.
It is important to work with a healthcare provider or mental health professional to identify coping strategies that are tailored to an individual’s specific needs and circumstances. With the right tools and support, individuals with short-term memory disorders can continue to lead fulfilling and meaningful lives.